Psilocybin-Assisted Therapy Achieves Positive Clinical Trial Results For Treating Generalized Anxiety

Psilocybin-assisted therapy has hit a milestone as clinical trial results show potential benefits for Generalized Anxiety Disorder (GAD.) 

With variable symptoms, the condition typically involves a person suffering from excessive anxiety and worry for over six months, potentially causing significant distress and impairment in social, occupational or other areas of functioning. A relatively common disorder, successful treatment of GAD remains inadequate, bringing on side effects and high costs.

The new topline clinical outcomes correspond to a Phase 2 study assessing psilocybin therapy's potential for treatment of Generalized Anxiety Disorder (GAD), conducted by clinical-stage cannabinoid and psychedelics biotech company Incannex Healthcare IXHL.

The trial met its primary endpoint, demonstrating a large clinical effect in the psilocybin treatment group over the placebo group: 

• The psilocybin group showed a total 12.8 reduction in HAM-A* scores from baseline (29.5) to Week 11, or six weeks post-final dosing session (16.8). 
• The psilocybin group's outcome represents a decrease of 9.2 points over the placebo group (3.6). 
• 44% of patients in the psilocybin arm showed a clinically meaningful improvement of at least 50% reduction in anxiety scores from baseline, a "response rate" over four times higher than that of the placebo group. 
• 27% of patients in the psilocybin group achieved full GAD remission, a rate over five times higher than that of psychotherapy with a placebo.
• Psilocybin was well tolerated, with reported mild and moderate adverse events that were consistent with the psychedelic's known effects, researchers said.
• No severe adverse events were observed. One of the 73 participants withdrew from the trial during the 7-week treatment program.

*The Hamilton Anxiety Rating Scale (HAM-A) is a clinician-based questionnaire assessing patients' severity of perceived anxiety symptoms. It is one of the most -if not the most- used scales within psychedelic clinical trials assessing their effects in anxiety-related disorders.

Next On The Horizon

"This is the first time psilocybin has been investigated for treatment of generalized anxiety disorder," said Incannex CEO and president Joel Latham, adding that the observed reduction in HAM-A scores is "far greater" than those reported from trials on traditional anxiety medicines and "of a similar magnitude" to that seen in clinical studies on psilocybin for depression disorders treatment. 

With a safe protocol and treatment design developed in partnership with Monash University's clinical psychedelic lab led by Dr. Paul Liknaitzky, the company has already designed the follow-up Phase 2b clinical trial (PsiGAD2) with a new partner, UK-based contract research organization Clerkenwell Health. 

The upcoming Phase 2b trial is planned to be conducted at multiple sites in the U.S. and the U.K. The new partners are working toward selecting the specific trial sites and preparing the regulatory documents for submission to both the FDA and the U.K.'s FDA, the Medicines and Healthcare Products Regulatory Agency (MHRA.)

Additionally, Incannex has completed the development of the formulation of its psilocybin drug product, PSX-001 and final preparations for the manufacture of the cGMP-compliant clinical trial batch are underway. 

Documentation on the formulation development and cGMP manufacture will form the final pieces of the Investigational New Drug (IND) application with the FDA that Incannex commenced in August 2023. The agency's clearance of the IND is required for the company to conduct the PsiGAD2 study at U.S. sites.

Learn more about the biotech company in this episode of Benzinga's Psychedelics Podcast.

Photo: Benzinga edit with photo by Tumisu and Sergeitokmakov on Pixabay.